An Avenger's Tail
by Aqualover5711
Summary: Post-Avengers AU in which Loki is now part of the Avengers. Loki and Thor wake up in a field somewhere with no idea how they got there. What's worse is that they're trapped in animal form without their powers. They are soon caught up in a crazy adventure, along with the rest of the Avengers, who have also been turned into animals. Who or what is responsible? Read to find out!
1. Chapter 1

**Author's Note: For those of you who have been reading my other Loki-centric story Trickster's Destiny, don't worry. I'm still writing that one as well. This idea just popped into my head and I couldn't resist giving writing a story from it a shot. For new readers, welcome aboard! I hope you guys enjoy this story full of adventure, drama, brotherly bonding, humor, and of course, some mischief courtesy of our favorite trickster :3, with a twist. I hope my story is original and fun but I'll leave that up to you, my reviewers to decide. Without further ado, I present to you the first chapter of An Avenger's Tail!**

"Brother! Wake up!" came Thor's booming voice. Loki groaned softly and muttered incoherently, wondering why this annoying nuisance was bothering him while he was trying to sleep.

"I'm sorry Loki but you have to get up!" Thor insisted. Loki could hear the edge of worry in Thor's voice and frowned slightly, wondering what could make the god of thunder sound so nervous. "Why is that Thor?" he mumbled sleepily.

Thor huffed and Loki felt something cold and wet nudge him in the shoulder. Startled, he cracked open his green eyes and blinked in confusion at what he was seeing. Looming over him was a large golden furred dog, his fur ruffled and his dark eyes wide with anxiety. It was a breed known as a golden retriever Loki recalled from a book he had read on Midgardian creatures. "Thor?" he asked in confusion.

"Aye, it is I Thor." Thor confirmed with a bark. He was pacing back and forth, trying to calm his nerves and regain his composure. Finally, he calmed a bit and turned to Loki once more, glaring down at him sternly.

Loki opened his eyes fully, and then grinned as he took in his brother's new form, his eyes glittering with amusement. "What happened to you?" he asked with a chuckle.

Thor growled. "I thought perhaps you had an answer to that Loki. Is this not one of your pranks?" he inquired, eyeing him suspiciously.

Loki scoffed. "Thor are you really so daft? Do you really think I would have been so foolish as to risk invoking your wrath and then fall asleep, leaving myself utterly defenseless?" he replied testily.

Thor nodded slowly. "Yes, I believe you're right. After all, I am certain you would also not be so foolish as to prank yourself as well." he commented thoughtfully, unable to suppress his laughter any longer.

Loki scowled at Thor, wondering just what was so funny. Thor's wagging tail thumped the ground as his shuddering laughs forced him into a crouching position. "I am sorry brother, but perhaps you should get up and examine yourself more closely." he managed to choke out.

Loki narrowed his eyes, but complied. He knew immediately something was off when he tried moving his legs. Looking down, his eyes widened and he let out a soft yelp of surprise as he glimpsed sleek black fur covering his entire body and a long tail flicking back and forth lazily. He had shifted into a black house cat! He rolled gracefully to his feet, full awake and alert now. He looked at Thor and then down at his paws, deep in thought. Had he lost control of his magic while he slept, turning himself and Thor, who shared a room with him, into animals?

He then realized something that shocked him even more. They weren't in their room in Stark Tower any more, nor anywhere else in the building. They seemed to be in a wide grassy field dotted with a few trees, an area that Midgardian's called a "park". What had happened last night exactly? No matter how hard he tried to remember, he just came up blank.

"Thor, what do you remember from last night?" he asked seriously.

Thor had finally gotten a hold of himself and was now sprawled on his back in the grass, seemingly enjoying the sunshine shining on his wavy gold fur. He flipped over so that he was lying on his stomach and met Loki's green eyes, still as piercing and calculating as ever despite the change in form. "I… don't remember anything either and it does concern me that we are now outside in a strange field. However, I say we should try to make the best of our newfound situation." he suggested optimistically.

Loki's tail twitched irritably and he had to suppress the urge to roll his eyes at his brother's cheeriness. A dog was a rather appropriate form for him: loud, obnoxious, and constantly happy. He sat down and licked his ruffled chest fur until it was sleek and smooth. "Yes, well, I'd rather just change back and return to the Tower now. The others might be wondering where we are by now, or you at the very least." he stated. He concentrated on his magic, but was alarmed to find it wasn't working. He tried again but to no avail. "Thor, my magic is gone! I can't change back!" he hissed, his fur fluffing out and his eyes panicked.

Thor stood and trotted to his little brother's side, pressing his side against his comfortingly. "Do not worry Loki. My power seems to be missing as well and I do not know how this occurred if it was not you who did it, but we will find out, together. In the meantime, let's rejoin our friends shall we? What say you brother?" he responded soothingly.

Loki stared at Thor for a moment before taking a deep breath and visibly relaxing, his fur lying flat, although his tail was still twitching a bit in agitation. He was a shape-shifter and therefore was used to being in many different forms, including this one, but this was different. This time he couldn't access his magic in order to shift back when he wished and that frustrated him to no end. He didn't understand how Thor was taking this so well, considering he had never been in another body besides his own, with the exception of the time Loki turned him into a frog after a fight when they were kids. He reluctantly nodded in consent. "Alright, but first we have to figure out where we are." he pointed out.

Thor tilted his head up and sniffed the air. "This creature has an amazingly good sense of smell. I believe I can figure that out in no time." he boasted.

Loki just grunted softly. He was too busy thinking how the other Avengers would laugh at him and Thor when they showed up at the tower like this to reply. Stark would never let him live this one down he thought bitterly.

He grudgingly ran after Thor as his overenthusiastic dolt of a brother suddenly bounded off in the direction he hoped led back home.

Little did either of them know that this was just the beginning of a long and wild journey that would change how they viewed the world, and each other, forever. What they also hadn't yet learned, was that they weren't alone on this crazy whirlwind adventure.


	2. Chapter 2

**Chapter 2**

The good news was that they were still in New York. Loki could see the city's skyline in the distance, growing closer as he and Thor continued their trek through the fields and forests on the outskirts of Manhattan.

The bad news was that neither of the Asgardians knew New York well enough to navigate the confusing maze of streets that would lead them back home. Loki figured that the audaciously tall Stark Tower would be easy enough to spot though and that they could then simply keep heading in that direction.

That turned out to be easier said than done though. Thor's nose eventually helped them arrive in the city after an exhausting hour in which Loki had stubbornly tried to ignore Thor when he insisted on incessantly talking the entire way.

They both looked warily at the busy sidewalks and streets full of honking cars and tons of mortals going about their mundane lives. They could indeed see their home, a shining beacon of cold steel in the distance, but how to get there?

"Come brother! Let us make haste! It is only a few more miles to go and then we can get this whole thing sorted out." Thor commanded eagerly.

Loki shook his head, sighing in exasperation. "Thor, do you not see all the cars and people in our way? I don't know about you, but I'd rather not be ran over or trampled to death. What a disgraceful way to die that would be." he muttered.

Thor chuckled. "Worry not Loki! We shall simply go through the alleys then! I have heard Stark say that they act as shortcuts, making our journey even shorter if we travel through them." he replied, not letting anything, even his brother's surly attitude, ruin his good mood. It was a nice day, he was getting to spend some quality time with Loki and despite the oddness and slight inconvenience of his situation, he was actually quite enjoying being a dog. He always loved finding new adventures and this was one for sure. It reminded him of the adventures he and Loki used to go on together as children, the way Loki would get them into trouble as much as he got them out of it.

Loki looked uncertain but just raised his tail in the air, lifted his chin, and with all the dignity he could muster, trotted off ahead of Thor into the nearest alley. Thor let out a bark of amusement and followed him in an easy lope, his longer legs easily allowing him to keep pace with the cranky feline.

After what seemed like endless walking, winding their way through alley after alley, avoiding other stray animals and homeless people along the way, and listening to Thor's continued babbling, they finally arrived at Stark Tower.

However, before either of them could make a move towards the front entrance, Loki heard a shout, a yelp from Thor, a sharp pang in his side, and then everything went black.

**Dun dun dun! What's going to happen to our favorite Asgardians next? A little hint, they are going to meet up with one of the other Avengers in the next chapter. :) Who will it be and what animal will they have become? What I can say for sure is that it's going to be a pretty exciting and funny chapter. Sorry if their journey back to the Tower seems a bit rushed and for the shorter chapter, but I wanted to get to the main part of the story so the adventure could really begin. The other chapters will be longer. Please review :D. Anyone who does gets a free Loki plushie (and this is for real) a link to my private collection of Loki fan-art X3!**


	3. Chapter 3

**Chapter 3**

**Author's Note: Thanks so much to the people who have reviewed! PieceOfMyHeart, I have taken your animal choices for Bruce into consideration :). Unfortunately though I haven't yet thought of how I want to bring him into the story or exactly what animal he'll be, so Loki and Thor won't be running into him until later. True to my word though, one of the other Avengers is indeed in this chapter. It's none other than our favorite snarky genius, billionaire, playboy, philanthropist :P. Hopefully the dialogue in this chapter makes you, my dear readers, laugh. I was laughing as I though it up. Enjoy!**

Loki groaned and once more blinked open his eyes to find himself in another weird situation. A quick examination told him two things: he was still a cat and he was in a cage. He got to his feet and peered out through the steel mesh keeping him trapped in the small box, noticing that the opposite wall also held rows and rows of cages, each with either a cat or dog occupying it. The bottom row had much larger cages that held the large dogs and that is where he found Thor, still knocked out and sprawled on his side. "Thor! Get up!" he hissed.

Thor pawed at his snout sleepily and then slowly stumbled into a sitting position, blearily opening his eyes. He looked around in alarm as he finally realized their new predicament. "Loki! Why have we been imprisoned?" he yelped. He stood and with a loud fierce bark, threw himself at the bars at the front of his cage, but they didn't budge.

Loki glared down at him coolly. "Thor, that won't work. You don't have your strength right now so you won't be breaking those bars. If you relax and let me think I will come up with a way to get us out of this." he said sternly.

He and Thor both froze as they heard a familiar sounding chuckle coming from the cage above Thor's and directly across from Loki's on the opposite wall. "Well, well, look what the cat dragged in." a small dark brown terrier mix yapped as he stepped into view from the back of his cage. Even in this form, there was no mistaking the arrogant swagger and devilish gleam in those dark brown eyes as he gazed at Loki, who just sighed wearily. So apparently it wasn't just he and Thor who had been transformed against their wills. Of all the Avengers they had to run into though.

"Man of Iron is that you?" Thor stated the obvious, wagging his tail like a puppy being given a treat.

"Yep, it's me Point Break, unfortunately. Well, it's not unfortunate being me, but it's unfortunate that I'm in this mess in the first place." Tony replied.

"Thor, don't you mean Mutt of Iron?" Loki quipped sarcastically.

Tony cocked his head to the side and then let out a yip of laughter. "Okay, that was a good one Reindeer Games." he chuckled. Then he stopped and looked at him seriously. "On to more important matters though. What the heck is going on? Why was I in my workshop one moment and then suddenly I'm waking up the next morning in a cage, with four legs and fur. Oh and I think I may have fleas." he muttered, turning and gnawing at his rear end in agitation.

Loki rolled his eyes. "You're embracing your new form a little too well I'd say." he snickered.

Tony turned his attention to him again. "Someone got up on the wrong side of the litterbox this morning." he retorted in slight annoyance.

Loki just huffed and turned his back on Stark, going to sniff at the disgusting smelling food in a small metal bowl at the back of his cage. He curled his lip in disdain but lapped up some of the water in the bowl next to it.

Tony gazed down at the floor of his cage like he could see Thor through it. "Hey MC Hammer, can you fill me in on what's happening. Did Loki do this?" he asked.

Thor shook his head although Tony couldn't see him. "No friend Stark. He says he did not and I trust him. He is one of us now. We don't have our powers at the moment though so my brother would not be able to do anything to us anyways. Neither of us is quite certain what has transpired here." he informed him.

"Uh-huh, and you believe this, coming from the god of lies? Well, I suppose I'll trust your judgment for now because I know Rock of Ages isn't stupid enough to prank himself as well." he said thoughtfully, although his tone was still slightly uncertain.

"Where exactly have we been taken to my friend?" Thor asked Tony in confusion.

"This is an animal shelter. It's a place where stray animals are taken off the streets and locked up until they're adopted. If they even are adopted. I swear, if the police put as much effort into cleaning up the streets with criminals as animal control does with strays, we Avengers would be out of the job. I woke up here and wherever you guys were, I guess they thought you guys were strays too, which I don't blame them." he answered with a teasing smirk in Loki's direction.

Loki lashed his tail as he paced in the cramped space. "Why don't you put that genius brain of yours to good use for a change Stark and help me figure a way out of here?" he grumbled impatiently.

"Aww, is the wittle kitty feeling lost without his fancy magic?" he taunted.

Loki's ears flatted against his head. "Don't tempt me Stark. Just because I don't have my abilities and I joined your team to redeem myself, does not mean that I am beyond giving you a few scars to remind you of your place." he snarled.

"Ooh, I think I touched a nerve." Tony laughed.

Thor let out a booming bark. "Be at peace my friends! Fighting will get us nowhere!" he yelled in his obnoxiously loud voice.

"Thor! Quiet down! We don't want to catch the attention of the mortals who run this place." Loki reprimanded.

Thor lowered his tail and looked at him sheepishly. "Sorry." he said quietly, or quiet for him anyway.

"Blondie is right though. Let's call a truce Loki okay?" Tony agreed.

Loki glanced back at him. He twitched his whiskers in contempt and narrowed his eyes but nodded. "Alright, for now." he consented grudgingly. He really was trying to get along with the Avengers more now, but he still found Tony Stark to be one of the most insufferable mortals he had ever met most of the time.

"So, are our other teammates here as well?" Thor asked hopefully, looking around.

"Nope. I don't know where they ended up. It seems like we were scattered to the winds on top of being turned into animals. I wonder what they ended up as?" Tony wondered as he plopped down in his cage and laid his head on his forepaws. "I hate to admit it, but while Loki would normally be right about not wanting to attract the workers' attention, we're not getting out of here by ourselves. If we want to escape, we need to cause a ruckus. The workers might open our cages to quiet us down or move us someplace else. We can use that opportunity to make our escape." he added as an afterthought.

Loki perked up at that idea and exchanged a meaningful look with Thor. They both grinned broadly, Thor's excited and Loki's mischievous. Tony eyed Loki wearily, knowing that look.

"Leave that to my brother and I Stark. Causing what you call a 'ruckus' is our specialty." Thor exclaimed proudly.

**Heh heh that was fun to write! The next chapter will be a funny one too; full of mischievous antics as the three Avengers make their Great Escape. I was originally going to put it in this chapter, but because I'm sick with a 102 degree fever at the moment, I decided to end the chapter and save the other part for the next chapter. Incidentally, that's also why it took so long to post. I actually started this this morning. Anyway, please remember to review if you like it! For my two reviewers and any future ones, I hope to have my fan-art site ready soon and I'll get the link to you guys then, if you still want it. For those who care, the next chapter of my Trickster's Destiny story is in the works and I'm hoping to get that updated tomorrow, before I write the next chapter of this one. I've just been busy/sick recently. I will not let that deter me from writing though! Oh, and one more thing. Although Thor is a dog, I couldn't resist making Tony a mutt, because I can totally picture him as a scruffy little terrier. I also couldn't help myself with the 'Mutt of Iron' quip :P. The other Avengers are all different animals though.**


	4. Chapter 4

**Author's Note: Sorry for taking so long to update! You know how things get during the holidays, plus school has started again. I meant to update my Trickster's Destiny story before writing another chapter of this, but I was bored in school and ended up writing this chapter in my free time. I have my next chapter of my other story pretty much figured out though so it shouldn't be long before I have that up as well. This chapter isn't quite what I wanted it to be, but I still like it and I hope you guys do too. Considering I wrote it while half-listening to my teacher, I think it turned out well.**

Loki took only a few minutes to come up with a plan. He looked at Thor with a small smile.

"Thor, put that appetite of yours to good use." he purred. Thor blinked, looking at his brother blankly for a second and then wagged his tail happily when he understood. He turned to his full food bowl. "I shall eat these hard food pellets with haste!" he exclaimed. Loki shook his head in amusement as Thor wolfed down his kibble, not even pausing to take a breath. When he was finished, he sat down and swiped his tongue around his snout contentedly.

"Good. Now, Thor, Stark, start howling. That should get the other dogs going as well. The mortals should come running soon enough. Watch for my signal to stop." Loki ordered.

Thor nodded enthusiastically while Tony just rolled his eyes, but they both raised their muzzles in the air and began howling as loud as they could. Loki smirked in satisfaction as the other dogs began to howl as well, either in excitement or irritation. The cats began making sounds of protest, adding to the cacophony.

Loki ruffled up his sleek black fur and laid down on his side, closing his eyes in preparation for his part in the plan.

Sure enough, three workers came running in, two men and a woman. One man shouted at them all to shut up. A few dogs startled and grew silent, but Thor and Tony kept up their howling, along with a few other dogs. The other man and woman exchanged glances, before the three of them began going around the large room, trying to calm the agitated animals.

Loki waved his tail and Thro and Tony ceased their howling immediately. The dogs who had been following them slowly stopped as well, whining and grumbling in confusion. The only other sounds now were the hisses of a few cats and a low moaning from Loki. He winked at Thor who perked his ears in acknowledgement. It was time to do what he did best, create total chaos.

The woman heard his sounds of distress and peered into his cage. "Are you not feeling well little kitty? Let's take you out and give you a check up. How does that sound?" she asked in sympathy. Loki twitched his whiskers indignantly at being called 'little kitty' and had to suppress the urge to swipe at her face with his claws. He opened his eyes slightly and watched intently as she pushed two steel hinges on the cage at the same time and pulled the door of his cage open with a metallic creak. She carefully reached in to pick him up and he allowed it, meeting Thor's gaze.

Thor barked loudly and nudged his bowl with his nose. The man who had shouted at them came over and glared at him. "What's gotten into you?" he grumbled. Thor stomped a front paw and nudged his bowl again. The man sighed in exasperation. "You already ate all your food? Fine, I'll get you one more scoop, but that's it for the day." he muttered. Thor panted gratefully.

The man left and after a few minutes returned, opening Thor's cage to put the scoop of food in the bowl. Thor grinned triumphantly and bowled the man over as he bounded out of his cage.

"Hey! Get back here!" the second man yelled. The two foolish humans not holding Loki ran after Thor, who dodged their grabbing hands, romping around playfully.

Loki suddenly sunk his teeth into his captor's hand. She yelped in pain and shock, dropping him. He landed gracefully on his paws and bolted forward, leaping fluidly onto the ledge in front of Tony's cage. He examined the mechanism keeping the cage closed, then with deft forepaws, he pushed down on one end and up on the other while balancing on his hind legs, like he had seen the woman do. The cage door popped open, almost causing Loki to fall. He dropped back onto all fours and jumped to the floor.

Tony scrambled down after him. "Nice work Rudolph. Now let's get out of here." he yipped.

Loki shot him a glare at the nickname, but focused his attention on the woman as she tried to catch him and Tony. They scrambled out of the way just in time.

"Come on Thor! Let's get out of here!" Loki called.

Thor had been playing tug-of war with both men, gripping a long stick with a loop on the end that he was biting. He let go and bounded after Loki and Tony, ignoring the shocked and angry shouts of all three people behind them. He shoved the glass door open and they made their escape.

Loki followed Tony as he led them as far from the animal shelter as they could get before they were too tired to continue, finally stopping in a copse of trees in what the mortals called Central Park, the very park Thor had taken him to after his defeat during the Chitauri invasion. Loki's flanks heaved slightly as he looked between his brother and the iron mutt.

Tony flopped onto the pinestraw and Thor was panting a bit. Thor and Loki exchanged grins and then they all started laughing as they recalled the looks on their captors' faces and because they were just happy to be free once more.


End file.
